1. Field of the Invention
This invention relates to photosensitive compositions. More particularly, the invention relates to photosensitive compositions which have a high resolving power and high reproducibility and which are suitable for use in the formation of relief images and in photo-etching processes.
2. Description of the Prior Art
Many systems are known in which a photosensitive synthetic resin is coated on a suitable support or substrate as a thin layer, and then the coated layer is exposed to light through a mask whereby the unexposed portion of the coated layer is removed by dissolution in a solvent leaving the exposed material behind. This type of procedure has been found useful in many industrial processes such as printing, precision processing, printed circuits, the manufacture of integrated circuits (IC) and the like. However, the conventional photosensitive resin systems have several disadvantages when used in these applications, and a number of improvements have been proposed to overcome these disadvantages. These improvements have been particularly applicable to processes in which fine line patterns must be reproduced such as in the photofabrication field, the electronics field, and particularly in the manufacture of integrated circuits, and LSI.
Certain factors affect the coating characteristics of the material which is coated. The most important factor is to achieve a coating which forms a thin uniform membrane on substrate such as metal plates, glass plates, silicon wafers and the like without the presence of pin holes in the membrane. The most important factor for determining the characteristics of the coating step is the combination of the photosensitive resin used with the solvent in the photosensitive compositions, and a need continues to exist for photosensitive resins which have a high reproducibility and high resolving power.